This invention relates to carton conveyors and more particularly to apron-type sortation conveyors provided with branch lines to which selected cartons can be diverted out of the main line. The present invention provides an addition to or an improvement on the sortation conveyors disclosed in the commonly owned applications of Thomas C. Yu et al, Ser. No. 675,156, filed Nov. 27, 1984, (hereinafter referred to as "Case A") and Ser. No. 857,915, filed Apr. 30, 1986 (hereinafter referred to as "Case B").
The invention is particularly concerned with such conveyors wherein the branch lines are arranged in directly opposed pairs along the main conveyor line, and the primaray object of the invention is to provide such a conveyor wherein such pairs of branch lines can be spaced as closely as possible to each other along the main line.
The sortation conveyor disclosed in Case A includes a frame defining the main line of the conveyor and at least one branch outlet therefrom, an endless apron supported for movement on the frame to define the top conveying run and a bottom return run, a plurality of pusher elements mounted for movement with the apron and also for sliding movement across the apron from one side thereof to the other, and selectively operable means for causing a desired number of pusher elements to move across the apron as they move forward with it and thereby to push the selected carton from the apron onto the selected branch conveyor.
More specifically, each of the pusher elements is equipped with a guide pin which depends therefrom, and when the pusher elements are in their normal rest positions along one side of the conveyor apron, each of these pins will pass in succession through a channeled switch member pivoted to swing between a retracted position parallel with the course of the apron and an advanced position at an acute angle to the apron course wherein it cooperates with the guide pins on successive pusher elements to divert those elements away from the side of the apron.
As soon as each diverter pin leaves the switch member, it is caused to engage a guide track which extends across the frame at an angle to the apron course. The forward movement of the pusher element with the apron will also cause it to be cammed by the guide track laterally across the apron and thereby to cooperate with successive similarly cammed pusher elements to push the selected carton onto the branch conveyor. Provision is made for returning each diverted pusher elements back to a rest position during its travel on the bottom return run of the apron back to the upstream end of the main conveyor line.
The operation of the conveyor disclosed in Case A requires that the guide pin on each diverted pusher element be continuously guided across the width of the apron until it completes its carton-ejecting movement. This is accomplished in that application by guiding the guide pin by means of a guide track extending at an angle across the entire width of the conveyor. That arrangement, however, requires that if it is decided to have branch outlets on both sides of the main conveyor, they cannot be located opposite each other but must be spaced alternately on the two sides of the main conveyor.
The conveyor disclosed in Case B includes all of the major components of the conveyor disclosed in Case A, and it also includes certain modifications and new components which make it possible to accommodate branch conveyors arranged in directly opposed pairs along the main conveyor line. More specifically, in the conveyor disclosed in Case B, provision was made for guiding a carton from the main conveyor line onto either of two directly opposed branch conveyors. This in turn required that provision be made for causing selected pusher elements to move from either side of the top apron run to the other side, depending upon the side of the main conveyor to which a particular carton is to be delivered.
In the conveyor disclosed in Case B, that objective is accomplished by the provision of a selective cross-over switching assembly which includes a pair of oppositely angled track elements positioned between the branch lines of an opposed pair in cross-defining relation. Each of these track elements, however, is in two parts which are spaced longitudinally from each other to provide a gap therein around the center of the cross which the two track elements define.
A supplemental guide element is mounted for switching movement within this gap area between two limit positions wherein it fills the gap in one or the other of the two-part track elements, depending upon which of the two branch conveyors is to receive a diverted carton. In other words, if a carton traveling on the main conveyor is to be diverted to a branch conveyor on the left, the appropriate number of pusher elements will be caused to begin diverting movement to the left for that carton, and at the same time, the supplemental guide element will be moved to the position wherein it fills the gap in the left-diverting track element so that each of the appropriate number of pusher elements will be guided completely across the top apron run to effect side delivery of the carton.
The supplemental guide element can remain in its left position until it is needed for delivery to the right-hand one of that pair of branch outlets. Then when the latter occasion arises, the supplemental guide element will be moved to its other limit position in order to assure proper operation of the number of pusher elements required to effect delivery of the selected carton to the right branch conveyor.
In the conveyor of Case B, however, it is still necessary that each pusher element travel across the entire width of the main conveyor line to complete the delivery of a carton to a branch conveyor. The primary objective of the present invention is to reduce that travel requirement, and thereby to make it possible to accommodate branch conveyors both in directly opposed pairs along the main conveyor line and also in more closely spaced relation lengthwise of the conveyor line.